Real-Time Adversarial Attacks

In recent years, many efforts have demonstrated that modern machine learning algorithms are vulnerable to adversarial attacks, where small, but carefully crafted, perturbations on the input can make them fail. While these attack methods are very effective, they only focus on scenarios where the target model takes static input, i.e., an attacker can observe the entire original sample and then add a perturbation at any point of the sample. These attack approaches are not applicable to situations where the target model takes streaming input, i.e., an attacker is only able to observe past data points and add perturbations to the remaining (unobserved) data points of the input. In this work, we propose a real-time adversarial attack scheme for machine learning models with streaming inputs.

Cite us:

If you feel this repository is helpful, please cite the following paper:

Yuan Gong, Boyang Li, Christian Poellabauer, and Yiyu Shi, "Real-time Adversarial Attacks", Proceedings of the 28th International Joint Conference on Artificial Intelligence (IJCAI), Macao, China, August 2019.

Dependencies

Tensorflow 1.0

Dataset

In the experiments of this work, we use the Speech Commands dataset (2.3GB), which is publically accessible. You don't need to download it if you want to train the target model from scratch because the training code will automatically download it.

How to run the code?

1. Download the dataset and train the target model

Clone this Github reporsitory. Then run:

python src/speech_model_train/speech_commands/train.py --data_dir data/

This will automatically download the Speech Commands dataset to the data directory and conduct the training. Note src/speech_model_train/train.py is an official tutorial example of Tensorflow 1.0 but is discontinued by Google. Information about the model can be found in the comments in the head of the file. We use all default settings and the model should have around 90% accuracy.

The default saved model can only infer one sample at a time. We recommend to modify it by using the provided src/speech_model_train/freeze_batch.py script to allow the saved model conduct batch inference. You need to:

1. Change line 86 of src/speech_model_train/freeze_batch.pyto your desired inference batch size (we use 50);
2. Run python src/speech_model_train/freeze_batch.py --start_checkpoint=/tmp/speech_commands_train/conv.ckpt-xxxx --output_file=/tmp/my_frozen_graph.pb

This will significantly speed up the next step of generating expert demostration samples. We include some pre-trained model with different inference batch size in src/speech_model_train/trained_models/.

2. Generate expert demonstration samples (i.e., non-real-time adversarial samples)

As mentioned in the paper, we generate the expert demonstration samples using a non-real-time adversarial example generation method, specifically, we use an audio version of the "one-pixel attack" (Jiawei Su, Vasconcellos Vargas, Sakurai Kouichi, IEEE Transactions on Evolutionary Computation, 2019).

The implementation of this is in src/generate_expert_demo.py. In line 242, the number of perturbed "pixels" (in the audio context, the number of purturbed segments) is defined, in this work, we use 5. In line 268, one sample is feeded to the attack model, where generate_perturbation_fix_scale is the key function, in which attack_fix_scale is the key function, in which differential_evolution is the key function. For differential_evolution, two important parameters are maxiter and popsize. Higher values for both do lead to better attack performance, but also increase the computation overhead, in this work, we use 75 and 10, respectively.

To run the code, first change the path of the target model and dataset in line 247 and line 251 and then run:

python src/generate_expert_demo.py

The perturbation result (n-dimensional vector of perturbation segment starting time in 0.01s, where n is the number of perturbation segment, e.g., if the result is [1, 10, 11, 22, 33], then the five perturbation start time is 0.01s, 0.1s, 0.11s, 0.22s, 0.33s) is saved in the location specified in line 211 as a .csv file. The perturbed audios will be saved in the loacation specified in line 212, and the log will be saved in the location specified in line 274. concatenate_script.m is used to pack all audio samples into three single csv files: original.csv, perturbation.csv, and label_info.csv. These are used for the next step.

Please note that since we needs to generate more than 10,000 samples, each involves an iterative evolution optimization algorithm, it can take a very long time (a few days) to finish. Parallelization can significantly accelerates the process, you need to first 1) modify and save a target model that allows batch inference; 2) use the src/differential_evolution module (authored by Dan Kondratyuk, 2018) instead of scipy.optimize.differential_evolution. The src/generate_expert_demo.py script has the parallelization implementation included, where we use the batch inference size of 50 (defined in line 42).

3. Learn from the demonstration samples

The src/train_attack.py train the real-time attack model using the original.csv, perturbation.csv, and label_info.csv files genereated from the previous step. The model architecture is in src/rnn_model.py. Change the file path in line 194-196 of src/train_attack.py to your path, and run: python src/train_attack.py. The attack model and the predicted perturbation on the test set are stored after training.

4. Analyze the attack result

Note that the predicted perturbation time of the attack model is NOT the actual perturbation time because the model may decide a start time that is earlier than the decision time, which is not possible to realize in the real-time setting. Therefore, we use a simple strategy that if the prediction time is earlier than the decision time, then immediately inject the perturbation. This is implemented in src/inject_attack.py.

Questions

If you have a question, please rasie an issue in this Github reporsity. You can also contact Yuan Gong ([email protected]).